System for neuromodulation

ABSTRACT

The present disclosure relates to a system for neuromodulation and/or neurostimulation, for the treatment of a subject. The system comprises a stimulation controller, a stimulation pattern storage means including stimulation data connected to the stimulation controller, an electrical stimulation device and electrical interface between the electrical stimulation device and the subject, the electrical interface being connectable with a bio-interface of the nervous system of the subject. The stimulation data are pre-programmed patterns comprising spatial and temporal components, The stimulation controller sends configuration signals on the basis of the stimulation data to the electrical stimulation device such that via the electrical interface electrical stimulation is provided to the bio-interface, wherein the electrical stimulation provided is characterized by stimulation parameters that vary over time in a pre-programmed manner.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No.17178950.6-1666, entitled “A SYSTEM FOR NEUROMODULATION,” filed on Jun.30, 2017, the entire contents of which is incorporated herein byreference in its entirety for all purposes.

BACKGROUND AND SUMMARY

The present disclosure relates to a system for neuromodulation and/orneurostimulation, for the treatment of a subject. The system is in thefield of improving recovery after neurological disorders such as spinalcord injury (SCI), and for example after disorders or injuries of thecentral nervous system.

EP 2 868 343 A1 discloses a system to deliver adaptive electrical spinalcord stimulation to facilitate and restore locomotion after neuromotorimpairment. Inter alia, a closed-loop system for real-time control ofepidural electrical stimulation is disclosed, comprising means forapplying to a subject neuromodulation with adjustable stimulationparameters, means being operatively connected with a real-timemonitoring component comprising sensors continuously acquiring feedbacksignals from subject, signals providing features of motion of a subject,the system being operatively connected with a signal processing devicereceiving feedback signals and operating real-time automatic controlalgorithms, and a signal processing device being operatively connectedwith the means and providing the means with new stimulation parameterswith minimum delay. This known system improves consistency of walking ina subject with a neuromotor impairment. A Real Time Automatic ControlAlgorithm is used, comprising a feedforward component employing a singleinput-single output model (SISO), or a multiple input-single output(MISO) model. Reference is also made to Wenger et al., Closed-loopneuromodulation of spinal sensorimotor circuits controls refinedlocomotion after complete spinal cord injury, in Science TranslationalMedicine, vol. 6, num. 255, 2014.

WO 2002/034331 A2 discloses a non-closed loop implantable medical devicesystem that includes an implantable medical device, along with atransceiver device that exchanges data with the patient, between thepatient and the implantable medical device, and between a remotelocation and the implantable medical device. A communication devicecoupled to the transceiver device exchanges data with the transceiverdevice, the implantable medical device through the receiver device, andbetween the transceiver device and the remote location to enablebi-directional data transfer between the patient, the implantablemedical device, the transceiver device, and the remote location. Aconverter unit converts transmission of the data from a first telemetryformat to a second telemetry format, and a user interface enablesinformation to be exchanged between the transceiver device and thepatient, between the implantable medical device and the patient throughthe transceiver device, and between the patient and the remote locationthrough the transceiver device.

US 2002/0052539 A1 describes a partial closed loop, non-continuous andnon-real-time emergency medical information communication system andcorresponding methods. The system permits an emergency alert to beissued on the basis of information sensed or processed by an implantablemedical device (IMD) implanted within a body of a patient. The IMD iscapable of bidirectional communication with a communication module, amobile telephone and/or a Personal Data Assistant (PDA) located outsidethe patient's body. The communication module, a mobile telephone or aPDA is capable of communicating an emergency alert generated by the IMDto a remote computer via a communication system. At the remote computersystem it may be determined that emergency remedial action is required.If so, the action is executed remotely from the remote computer systemin the IMD via the communication system.

Known stimulation systems use either Central Nerve System (CNS)stimulation, especially Epidural Electrical Stimulation (EES), orPeripheral Nerve System (PNS) Stimulation, especially FunctionalElectrical Stimulation (FES).

Epidural Electrical Stimulation (EES) is known to restore motor controlin animal and human models and has more particularly been shown torestore locomotion after spinal cord injury by artificially activatingthe neural networks responsible for locomotion below the spinal cordlesion (Capogrosso, M, et al., A Computational Model for EpiduralElectrical Stimulation of Spinal Sensorimotor Circuits, Journal ofNeuroscience 4 Dec. 2013, 33 (49) 19326-19340, Courtine et al.,Transformation of nonfunctional spinal circuits into functional statesafter the loss of brain input, Nat Neurosci. 2009 October; 12(10):1333-1342. Moraud et al, Mechanisms Underlying the Neuromodulation ofSpinal Circuits for Correcting Gait and Balance Deficits after SpinalCord Injury, Neuron Volume 89, Issue 4, p 814-828, 17 Feb. 2016). EESdoes not directly stimulate motor-neurons but the afferent sensoryneurons prior to entering into the spinal cord. In this way, the spinalnetworks responsible for locomotion are recruited indirectly via thoseafferents, restoring globally the locomotion movement by activating therequired muscle synergies. The produced movement is functional; however,due to relatively poor selectivity (network activation instead ofselective targeting of key muscles) the controllability is low and theimprecisions hinder fluidity and full functionality in the potentialspace of the movement.

Peripheral Nerve System (PNS) Stimulation systems used to date in theclinic are known as Functional Electrical Stimulation (FES) thatprovides electrical stimulation to target muscles with surfaceelectrodes, either directly through stimulation of their motorfibers(neuro-muscular stimulation), or through a limited set reflexes(practically limited to the withdrawal reflex) or by transcutaneouslystimulating the peripheral nerves. The resulting muscle fatigue hasrendered FES unsuitable for use in daily life. Furthermore, successeshave remained limited through cumbersome setups when using surfacemuscle stimulation, unmet needs in terms of selectivity (when usingtranscutaneous nerve stimulation) and a lack of stability (impossible toreproduce exact electrode placement on a daily basis when stimulatingmuscles, moving electrodes due to clothes, sweating, etc.).

It is an object of the present disclosure to improve a neuromodulationsystem, for example in the field of improving recovery afterneurological disorders like spinal cord injury (SCI), for example aftertrauma or stroke or illness. Importantly, neuromodulation and/orneurostimulation may be provided in almost any environment and in dailylife, may be adapted to a patient's needs and may provide the desiredassistance in training and daily life for the patient, an may further beadjusted to the progress of the rehabilitation of the patient.

This object is solved according to the present disclosure by a systemfor neuromodulation and/or neurostimulation, for the treatment of asubject. Accordingly, a system for neuromodulation and/orneurostimulation, for the treatment of a subject is provided, comprisingat least a stimulation controller, at least a stimulation patternstorage means, also referred to herein as a stimulation pattern storagedrive, which is connected to the stimulation controller and whichcomprises stimulation data, at least an electrical stimulation device,at least an electrical interface between the electrical stimulationdevice and the subject, the electrical interface being connectable withat least a bio-interface of or with the nervous system of the subject,wherein the electrical interface and the bio-interface are arranged suchthat signals and/or data may be exchanged from the electrical interfaceto the bio-interface, or vice versa, wherein the stimulation data arepre-programmed patterns, which comprise at least a spatial component,which is related to a part of the nervous system being stimulated, atemporal component, which is related to a time at which each spatialcomponent mentioned above is applied, and wherein the stimulationcontroller is capable to send configuration signals on the basis of thestimulation data to the electrical stimulation device such that via theelectrical interface electrical stimulation may be provided to thebio-interface, wherein the electrical stimulation provided ischaracterized by stimulation parameters that vary over time in apre-programmed manner.

The present disclosure is based on the basic idea that in the context ofneuromodulation and/or neurostimulation, the electrical stimulationparameters defining the stimulation for the subject to be treated mayvary cyclically over time in a pre-programmed manner, for example onecycle with pre-defined timings for the various stimulation patterns maybe repeated over and over again. The use of pre-programmed temporalstimulation pattern data together with the use of pre-programmed spatialstimulation pattern data may allow a stimulation at a correct place at acorrect time to facilitate, enable, or trigger an intended action of thesubject. Such an action may be movement of extremities like feet and/orlegs and/or arms, contraction and/or relaxation and/or any movement ofmuscles in connection with movement of the subject or cardiovascularfunctions of the subject (e.g. blood pressure control and/or bloodcirculation support and/or blood circulation control). Such an approachmay be characterized as open-loop phasic stimulation. Basically, it mayform a way to stimulate phasically the nervous system, for example thespinal cord of a subject or patient without the need for complex and/orcomplicated feedback systems. It may easily be implemented to promotelocomotion, cyclical activity with physical training devices, and reduceorthostatic hypotension, after nervous system impairments such as spinalcord injury. Thus, it may be possible to improve a neuromodulationsystem, e.g. in the field of improving recovery after neurologicaldisorders like spinal cord injury (SCI), for example after trauma orstroke or illness, in that neuromodulation and/or neurostimulation maybe provided in almost any environment and in daily life, may be adaptedto the patient's needs and may provide desired assistance in trainingand daily life for the patient, and may be further adjusted to theprogress of the rehabilitation of the patient.

According to an embodiment of the system, the stimulation patternstorage means may comprise a spatial stimulation pattern data storagemodule for storing the spatial component, and the stimulation patternstorage means may comprise a temporal stimulation pattern data storagemodule for storing the temporal component, wherein the stimulationcontroller is capable to access the modules and/or to read out themodules independently from each other. This may allow easier and fasteraccess to the different kinds of data and thus a faster process andstimulation may be possible. The link between the different kind of datamay be established for example by meta data, such that the meta dataform the link between the temporal component and the spatial component.

The stimulation pattern data may comprise data related to at least oneof the parameters including stimulation frequency, stimulationamplitude, stimulation current, and/or pulse width. Generally speakingthe stimulation pattern data may comprise data characterizing thestimulation to be applied.

Moreover, the electrical stimulation device may comprise a plurality ofelectrodes and the spatial component may comprise data related to theactivation and non-activation of defined subsets of electrodes. By this,it may be possible to control and/or steer which part of the nervoussystem shall be stimulated. Subsets of electrodes may be defined as anyvalue x out of the range 0 to n, n being the number of electrodesavailable. The plurality of electrodes may be arranged in an array, e.g.in an electrode array on a stimulation lead. Such a stimulation lead maybe a lead paddle or a lead wire, or any kind of lead or carrier(s)having at least one lead or carrying at least a partial number of theelectrodes.

The stimulation pattern data may comprise meta data, which may link thetemporal component and spatial component to each other. This may allowfaster access to the data and a faster and more efficient use of thestimulation pattern storage means. Also, a reprogramming may besimplified, as only additional or replacing meta data may have to beprovided.

In an embodiment, the stimulation pattern data may comprise a sequenceof stimulation patterns for a cyclic activity. As a cyclic activity inthe broadest sense may be defined as a sequence of predefined movements,such sequence of movements may be assisted by a corresponding sequenceof stimulation patterns provided by the system. In this way,rehabilitation of patients may be assisted and improved. Such a cyclicactivity may be inter alia (but not limited to) a gait cycle, cycling,swimming, a rehabilitation activity and/or a training activity.

The sequences may comprise a plurality of ordered stages which may bearranged such that they form in their order a replication ofphysiological activation signals of relevant muscle groups at anappropriate time for a specific task or movement of the subject, thespecific task or movement being at least one of walking, standing,standing up, sitting down, climbing staircases, cycling, lifting a foot,placing and/or moving an extremity, trunk, and/or head of the subject,and the like.

A stage being used in the context that an open-loop phasic stimulationprogram is a pre-defined sequence of stages that may activate severalsets of active electrodes that in turn affect several muscle groups.

Thus, for specific movements specific matching sequences may beprovided. Sequences may comprise a succession of well-timed sequences inorder to replicate the activation of relevant muscle groups at anappropriate time as they would be for a specific task, the specific taskbeing walking, standing, climbing staircase, cycling, etc.

The sequences may be part of an open-loop phasic stimulation. In thismode, electrode stimulation parameters may vary cyclically over time ina pre-programmed manner, i.e. one cycle with pre-defined timings for thevarious stimulation patterns (sites, frequency, amplitude, pulse width,etc.) may be repeated over and over again.

Such an open-loop phasic stimulation may be for example applied in thecontext of Epidural Electrical Stimulation (EES) with one or moreimplantable pulsegenerator(s) and epidural electrodes, which may beinvasive and may be implanted in the spinal channel. The implantablepulse generator(s) and epidural electrodes (e.g. in the form of anelectrode paddle with an array of electrodes) may be implanted minimallyinvasive or invasive. The epidural electrodes may be implanted in thevertebral channel through minimally-invasive or invasive surgicaltechniques. However, the system is not limited to such an application.Generally speaking, stimulation electrode arrays may also benon-invasive, e.g. by administering and providing transcutaneousstimulation to the spinal cord and/or other parts of the nervous system.Open-loop phasic stimulation may be also provided with externalstimulators and invasive and/or non-invasive electrodes, such as inFunctional Electrical Stimulation (FES) of individual muscles,Peripheral Nerve System (PNS) Stimulation of peripheral nerves and/or intranscutaneous spinal cord stimulation. It is also in general possible,that the afore-mentioned stimulation approaches may be combined.

Possible stimulation parameters for use in open-loop stimulation may besummarized as follows:

Frequency: 10-1000 Hz with preferred frequencies between 60 and 120 Hz.

Pulse Width: 100-1000 μs for implanted electrodes (invasive) and200-2000 μs for surface electrodes (non-invasive and transcutaneousstimulation).

Amplitudes: 0.1-25 mA or 0.1-15 V for implanted electrodes (invasive)and 1-250 mA or 1-150 V for surface electrodes (non-invasive andtranscutaneous stimulation).

Pulse shape: any type of charge-balanced pulse, either monophasic orbi-phasic.

Duration of each stage (i.e. stage being used in the context that anopen-loop phasic stimulation program is a pre-defined sequence of stagesthat can activate several sets of active electrodes that in turn affectseveral muscle groups): 50-5000 ms.

Number of stages: approx. 1-10 (also other ranges possible, e.g. higheror lower then 10).

For example, the sequences for walking may comprise at least a firstsequence related to left flexion and right extension, a second sequencerelated to right extension only, third sequence related to leftextension and right flexion and a fourth sequence related to leftextension only. Here, for example the first sequence related to leftflexion and right extension may be approx. 400 ms, the second sequencerelated to right extension only may be approx. 600 ms, the thirdsequence related to left extension and right flexion may be approx. 400ms and the fourth sequence related to left extension only may be alsoapprox. 600 ms. Other suitable values may be chosen. In particular, thesequences related to extension only may be chosen with a longer durationthan the sequence for flexion on one side and extension on the otherside, e.g. approx. 1.5 times longer.

Furthermore, the stimulation pattern data may comprise a sequence ofstimulation patterns exploiting a skeletal muscle pump for blood pumpingfrom the extremities of the subject in the direction back to the heartof the subject. By this, it may be possible to assist the subject withblood pressure control and to avoid a blood pressure drop when thesubject or patient wants to stand up, e.g. during rehabilitation forstretching in a standing frame in preparation to walk or generally forstarting to walk or the like. Also, during walking such a stimulationmay help the patient to perform his/her training.

The sequences may comprise at least a first sequence related tostimulation of a muscle in at least one extremity to contract the muscleand at least a second sequence related to stimulation of a muscle inthis extremity to relax the muscle. The second sequence may have a lowerstimulation or simply no stimulation may be provided. By this, a verysimple but effective blood pumping may be realized.

In particular, the system may be an open-loop system. With such anopen-loop system open-loop phasic stimulation may be provided.

In particular, open-loop may be understood as delivery of pre-programmedspatiotemporal stimulation or pre-programmed spatiotemporal stimulationpatterns with spatial and temporal components.

The stimulation data for delivery of pre-programmed spatiotemporalstimulation or pre-programmed spatiotemporal stimulation patterns withspatial and temporal components may be pre-programmed patterns, whichmay comprise at least

a spatial component, which is related to the part of the nervous systembeing stimulated

a temporal component, which is related to the time at which each spatialcomponent mentioned above is applied.

In contrast to closed-loop systems, open-loop may be understood suchthat neuromodulation and/or neurostimulation is provided, but feedbackfrom the patient is not used or does not influence the stimulation data.Also, the stimulation provided by the stimulation device, inter alia thesequences provided, may be maintained. Under these unchanged stimulationsequences, when stimulation is applied to afferent sensory neurons priorto entering into the spinal cord or in the periphery, the patient maystill influence—to some degree—an extent of a generated motor output bycontributing more or less volitionally. Likely, stimulation-inducedinputs to the spinal cord and volitional descending activity may beintegrated at pre-motoneuronal and motoneuronal levels in the spinalcord and hence may influence each other and the amount of motor activitygenerated. As a consequence, the patient may, with unchanged stimulationfrequencies, amplitudes, or pulse-widths within the pre-definedsequences of stimulation, exaggerate or suppress the generated motoroutputs—to some degree—by contributing more or less volitionally. In anycase, this may allow a simplified and reliable system. Also, the systemmay be less complex. It may form an additional system and/or supplementfor existing systems or other systems.

For example, it may be possible that the system comprises and/or isconnected and/or is connectable with a closed-loop system forneuromodulation and/or neurostimulation. Thus, a closed-loop andopen-loop system may be provided and established. This may allow the useof the open-loop approach for specific, predefined tasks, whereas theclosed-loop approach may be used for other tasks, where the closed-loopapproach may promise more effect. A broader range of stimulationcapabilities may be provided by such a combination.

The closed-loop system may work in real-time or may be—in other words—areal-time system such that feedback data being sensed by the system areprocessed as input variables for control of the system, and that thisprocessing is done in real-time.

Real-time may be understood as real-time or close to real-time. Interalia, a time frame and short delay between 0.0 to approximately 30 msmay be understood to fulfill the condition of real-time.

Furthermore, the system may be configured such that the stimulation datamay be re-configured and/or adjusted on the basis of data beingdelivered by the closed-loop system, especially wherein there-configuration and/or adjustment is done in real-time. There may be areal-time configuration of the pre-programmed stimulation pattern. Inparticular, the closed-loop system and its data may be used to adapt thestimulation data of the open-loop system. Such closed-loop system datamay be delivered to the stimulation controller, which then may modifythe stimulation data. In other words, the closed-loop system may be usedto re-configure and/or adjust the stimulation data of the open-loopsystem.

The spatial component and the temporal component may be, as one example,configured by using the closed-loop system (or a closed-loop system),based for example on movement feedback on a cycle to cycle basis (e.g.as opposed to triggering events).

Also, the sequence of stimulation patterns may comprise at least onestarting sequence. For example, the starting sequence may be forstarting a cyclic activity (cf. above), like a gait cycle or the like,facilitated and/or induced by the feedback-controlled closed-loop phasicstimulation system as described above. It has been observed thatmaintaining an existing movement or sequence of movements is easier tomaintain than to start it. Surprisingly, it has been found that evenwith a well-adjusted sequence of stimulation patterns, e.g. for a gaitcycle, the patient to be treated has to try hard to start the gait cycleand the specific movement. By providing a starting sequence, whichtriggers the start of the gait cycle and the specific movements, betterassistance for the patient may be provided. The starting sequence forstarting the gait cycle is for example applied only at the beginning ofa training sequence of the gait cycle, then followed by an iterativelyapplied sequence of stimulation patterns for the gait cycle. This kindof paradigm is, however, not limited to training or rehabilitationscenarios, but may also be used in daily life for assistance of users ofsuch a system in order to enhance the movement capabilities of suchpatients and to increase their independence from caregiving.

It may be possible that the system may comprise an initialization moduleand initialization data, the initialization data being specificstimulation data being stored in the stimulation pattern storage means,wherein the initialization module is configured and arranged to controlthe electrical stimulation device based on the initialization data suchthat electrical stimulation device provides neuromodulation signalsand/or neurostimulation signals, for an initialization action ormovement of the subject. With such an initialization capability, thestart of a specific movement or task may be facilitated. In particular,specific tasks like walking, standing, standing up, sitting down,climbing staircases, cycling, lifting a foot, placing and/or moving anextremity or the head of the subject and the like may be started, andafter this initialization, supported by the system itself with open-loopphasic stimulation (or the stimulation is done by another system).

For example, the system may be configured and arranged such that theinitialization module and initialization data are used to start theclosed-loop system. It has been found that open-loop stimulation may bevery beneficial and effective to “start-up” the task and to provide andtrigger the start of the task, whereas during the task closed-loopstimulation may be provided.

Also, the system may comprise a fallback module and fallback moduledata, the fallback module data being specific stimulation data beingstored in the stimulation pattern storage means, wherein the fallbackmodule may be configured and arranged to control the electricalstimulation device based on the fallback module data such thatelectrical stimulation device provides neuromodulation signals and/orneurostimulation signals, for actions or movement of the subject, whenthe closed-loop system is unintentionally out of service. By this, theoverall safety of a closed-loop system may be increased and enhanced. Insuch a case, the system itself has the capability to provide open-loopstimulation and closed-loop stimulation or the system is combined with aclosed-loop system. As open-loop stimulation does not require anyreal-time information from the leg movement and positions of thepatient, such an approach may be advantageous to maintain and provide atleast basic stimulation capabilities, when closed-loop stimulation istemporarily not working (e.g., temporarily fails to detect or decodespecific gait events otherwise triggering specific stimulationsequences).

In particular, it is possible that the fallback module data areneurostimulation signals, for actions or movement of the subject, whenthe closed-loop system for said subject being connected with the systemis unintentionally out of service. Thus, a fallback functionality forthe closed-loop system may be provided. Even with a system failure ofthe closed-loop system it may still be possible to provide open-loopphasic stimulation. Thus, for example in a scenario for stimulation ofthe legs, a patient may still be able even in case of a system failureof the open-loop system to reach his/her wheelchair, or simply continuewith moving. This may also provide enough time for allowing theclosed-loop system to restart.

Combinations of an open-loop system as defined above in connection witha closed-loop system maybe also called “hybrid systems”.

As described above, in such hybrid systems open-loop stimulation andclosed-loop stimulation may assist each other or form a combinedopen-loop and closed-loop stimulation system. Thereby, it may be allowedto have open-loop stimulation and closed-loop stimulation at the sametime, e.g. to allow and trigger additional movements by means ofopen-loop stimulation during walking assisted by closed-loopstimulation. In this context possibilities are not restricted to thisexample and other examples are possible.

Also, such hybrid system may comprise—additionally or alternatively—afallback solution, in particular open-loop stimulation as fallback forclosed-loop stimulation.

The hybrid system approach may also be used to form an enhancedstimulation system with easier system initialization by means ofassisting movement initialization with open-loop phasic stimulation, inparticular as described above in connection with the initializationmodule and the initialization data and the starting sequence.

Furthermore a method for neuromodulation and/or neurostimulation, forthe treatment of a subject, is explicitly disclosed. Accordingly, amethod for neuromodulation and/or neurostimulation, for the treatment ofa subject is provided, wherein the method may be performed by using atleast an electrical stimulation device and at least an electricalinterface between the stimulation device and the subject, and at least asubject neural interface, being connected to the electrical interface,wherein the subject may be stimulated with the electrical stimulationdevice by using stimulation pattern data and wherein the stimulationdata are pre-programmed patterns, which comprise at least

a spatial component, which may be related to the part of the nervoussystem being stimulated

a temporal component, which may be related to the time at which eachspatial component mentioned above is applied

and wherein on the basis of the stimulation pattern data the electricalstimulation device provides via the electrical interface electricalstimulation to the subject neural interface, wherein the electricalstimulation provided may be characterized by stimulation parameters thatvary over time in a pre-programmed manner.

Furthermore, the method may be performed by using the system forneuromodulation and/or neurostimulation as specified above.

Also, it may be possible that the electrical stimulation may be providedin sequences and/or cyclically and/or repeatedly.

Additionally, the electrical stimulation may be provided in sequenceswhich comprise a plurality of ordered sequences which are arranged suchthat they form in their order a replication of the physiologicalactivation signals of relevant muscle groups at an appropriate time fora specific task or movement of the subject, the specific task ormovement being at least one of walking, standing, standing up, sittingdown, climbing staircases, cycling, lifting a foot, placing and/ormoving an extremity or the head of the subject, and the like.

As an example, for walking that the electrical stimulation may addressin the legs and feet of the subject at least

in a first step left flexion and right extension,

in a second step right extension only,

in a third step left extension and right flexion,

in a fourth step left extension only.

It may also be possible that the electrical stimulation stimulatesmuscles of the subject for blood pumping from the extremities of thesubject in the direction back to the heart of the subject, for examplewherein at least one muscle is stimulated such that the muscle contractsand relaxes alternately.

BRIEF DESCRIPTION OF THE FIGURES

Further details and advantages of the present disclosure shall now bedisclosed in connection with the drawings.

FIG. 1 shows a schematic view of the layout of an embodiment accordingto the present disclosure of the neuromodulation and/or neurostimulationsystem.

FIG. 2 shows an example workflow diagram of the system of FIG. 1.

FIG. 3 shows a schematic diagram of the leg and feet trajectory.

FIGS. 4A-D show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for a gait cycle stimulation.

FIG. 5 shows a schematic overview of the concept of open-loop phasicstimulation for walking.

FIGS. 6A-B show a schematic overview of the training of a patientwithout and with open-loop phasic stimulation by using the system asshown in FIG. 1.

FIGS. 7A-B show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for left leg stimulation.

FIGS. 8A-B show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for stimulation for walking withan ambulatory walker.

FIGS. 9A-B show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for stimulation for walking at anenhanced rehabilitation stage (challenging scenario).

FIGS. 10A-B show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for sacral stimulation to improvesexual function and bladder function.

FIGS. 11A-B show a schematic view of an electrode paddle of the systemwith specifically activated electrodes for knee extension stimulation tofacilitate sit-to-stand scenarios.

FIGS. 12A-B show a schematic view of the principle of a skeletal musclepump by using the system according to FIG. 1.

FIG. 13 shows a schematically view of the implanted system and thesubject being equipped with the system FIG. 1 together with a closedloop system.

DETAILED DESCRIPTION

FIG. 1 shows in a schematic view the layout of the neuromodulationand/or neurostimulation system 10 according to the present disclosure.

The system 10 is a system for improving recovery after neurologicaldisorders such as spinal cord injury (SCI), for example after disordersor injuries of the central nervous system.

The system 10 as shown is an open-loop phasic stimulation system 10.

The system 10 comprises a controller 12.

The controller 12 comprises also an input means 12 a, which isconfigured and arranged to provide the controller 12 with additionalinput signals.

Such input signals may be alternative and/or additional stimulationdata, which are provided to and installed on the system 10.

Moreover, the controller 12 comprises an interface 12 b, which isconfigured and arranged to connect the controller 12 with other systems(not shown). Such system may be, inter alia and not limited to, e.g.another closed-loop system for neuromodulation and/or neurostimulationfor the treatment of a patient.

Furthermore, there is a stimulation pattern storage means 14.

In the stimulation pattern storage means 14 stimulation data SD arestored and available for the system 10.

The stimulation data SD comprise data related to at least one of theparameters stimulation frequency and/or stimulation amplitude and/orstimulation current and/or pulse width or the like or other suitableparameters, either direct parameters or indirect relevant parameters.Generally speaking the stimulation data may comprise data characterizingthe stimulation to be applied.

The stimulation data SD comprise pre-programmed patterns, which compriseat least

a spatial component SC, which is related to the part of the nervoussystem being stimulated

a temporal component TC, which is related to the time at which eachspatial component mentioned above is applied.

The stimulation pattern storage means 14 has a spatial stimulationpattern data storage module 14 a for the spatial component and atemporal stimulation pattern data storage module 14 b for the temporalcomponent.

The stimulation pattern storage means 14 also has a meta data storagemodule 14 c for storing meta data MD.

The meta data MD link the temporal component and spatial to each other.

Furthermore, there is an electrical stimulation device 16. Thestimulation device 16 comprises the necessary electronics like a pulsegenerator 16 a and/or an interface 16 b being connectable to a pulsegenerator.

The pulse generator may be an Implantable Pulse Generator (IPG) or anexternal or non-implantable pulse generator.

There is an electrical interface 18 of the system 10.

The interface 18 may be formed by or comprise one or more electrodes 18a, 18 b.

Here, the electrodes 18 a may be implanted or implantable electrodes andthe electrodes 18 b may be electrodes for providing stimulationnon-invasively and transcutaneously.

The electrodes 18 a are preferably arranged in an electrode array. It ispossible that the electrodes 18 a are part of an electrode paddle (e.g.19) for spinal cord stimulation.

The spatial component SC comprises data related to the activation andnon-activation of defined subsets of electrodes 18 a, 18 b. Also, thesedata may comprise the information as to whether the electrode isactivated as cathode or anode. By this, it may be possible to controland/or steer the exact site of the nervous system that shall bestimulated. Subsets of electrodes may be defined as any value x out ofthe range 0 to n, n being the number of electrodes available.

The interface 18 is in contact with a bio-interface 20 of the subject tobe treated with the system 10. There can be several bio-interfaces 20.

As further shown in FIG. 1, the system 10 comprises an initializationmodule 22.

In the stimulation pattern storage means 14 initialization data ID arestored and made available for the system 10.

The initialization data ID are specific stimulation data being stored inthe stimulation pattern storage means 14. It is also possible to storethe initialization data ID directly in the initialization module 22.

The initialization module 22 is configured and arranged to control theelectrical stimulation device 16 via the controller 12 based on theinitialization data ID such that the electrical stimulation device 16provides neuromodulation signals and/or neurostimulation signals, for aninitialization action or movement of the subject.

As a special functionality, the system 10 may be configured and arrangedsuch that the initialization module 22 and initialization data ID areused to start a closed-loop system. For this, e.g. the interface 12 bmay be used.

Also, the system 10 comprises a fallback module 24.

In the stimulation pattern storage means 14 fallback module data FD arestored and made available for the system 10.

The fallback module data FD are specific stimulation data being storedin the stimulation pattern storage means 14. It is also possible tostore the fallback module data FD directly in the fallback module 24.

The fallback module 24 is configured and arranged to control theelectrical stimulation device 16 via the controller 12 based on thefallback module data FD such that electrical stimulation device 16provides neuromodulation signals and/or neurostimulation signals, foractions or movement of the subject, when the closed-loop system isunintentionally out of service.

The components of the system 10 are linked as follows:

The controller 12 is connected with the stimulation pattern storagemeans 14, the electrical stimulation device 16, the initializationmodule 22, and the fallback module 24.

The stimulation device 16 is in connection with the interface 18, i.e.with the electrodes 18 a and 18 b. Thus, the stimulation device 16 mayprovide stimulation via the interface 18, i.e. via the electrodes 18 aand 18 b.

In operation, the electrical interface 18 is connected with thebio-interface 20 of or with the nervous system of the subject, whereinthe electrical interface 18 and the bio-interface 20 are arranged suchthat signals and/or data may be exchanged from the electrical interface18 to the bio-interface 20.

It may be possible that in cases with combinations of open-loop andclosed-loop, the data exchange between the electrical interface 18 andthe bio-interface 20 may be also vice versa.

Such a data exchange may be established via input means 12 a andinterface 12 b.

The stimulation controller 12 is capable to access the spatialstimulation pattern data storage module 14 a and the temporalstimulation pattern data storage module 14 b and to access and read outthe modules independently from each other.

This may allow easier and faster access to the different kind(s) of dataand thus a faster process and stimulation may be provided by the system10.

The link between the different kind(s) of data is established by meansof the meta data MD stored in the meta data storage module 14 c, suchthat the meta data MD form the link between spatial component SC andtemporal component TC.

So, the stimulation pattern storage means 14 provides storage capacityfor data, inter alia control instructions for performing the control ofthe system 10 by means of the controller 12, which is capable to controlthe overall system based on the instructions stored in the stimulationpattern storage means 14.

Such instructions include but are not limited to stimulation sequencesas follows:

Inter alia, in the shown embodiment the stimulation data SD comprise asequence of stimulation patterns for a gait cycle, i.e. a predefinedsequence of stimulation of specific sites of the CNS and/or PNS forrecruiting muscle groups to facilitate movements.

Also, the sequence of stimulation patterns for a gait cycle may compriseat least one starting sequence for starting the gait cycle.

Then, the sequences comprise a plurality of ordered sequences which arearranged such that they form in their order a replication of thephysiological activation signals or signal pattern of relevant musclegroups at the appropriate time for a specific task or movement of thesubject, the specific task or movement being at least one of walking,standing, standing up, sitting down, climbing staircases, cycling,lifting a foot, placing and/or moving an extremity or stabilizing thetrunk of the subject and the like.

Thus, for specific movements specific matching sequences may beprovided. Sequences may comprise a succession of well-time sequences inorder to replicate the activation of relevant muscle groups at anappropriate time as they would be for a specific task, the specific taskbeing walking, standing, climbing staircase, cycling, etc.

The sequences may be part of an open-loop phasic stimulation. In thismode, electrode stimulation parameters may vary cyclically over time ina pre-programmed manner, i.e. one cycle with pre-defined timings for thevarious stimulation patterns (sites, frequency, amplitude, pulse width,etc.) may be repeated over and over again.

The function of the system 10 e.g. during a treatment and/orneurorehabilitation training of a patient may be described as follows.

The system 10 provides open-loop phasic stimulation.

In this mode, electrode stimulation parameters vary cyclically over timein a pre-programmed manner, i.e. one cycle with pre-defined timings forthe various stimulation patterns (sites, frequency, amplitude, pulsewidth, etc.) is repeated over and over again.

The system 10 provides open-loop phasic stimulation in the context ofEpidural Electrical Stimulation (EES) with one implantable pulsegenerator(s) and an epidural electrode array on an electrode paddle (cf.also FIG. 3A-D), which is implanted in the epidural space.

However, the system is not limited to such an application. It mayconsist of several epidural electrode arrays arranged over the lumbar,thoracic, and cervical spinal cord (and connected to more than oneimplantable pulse generator) for the control of lower extremity, trunk,and upper extremity function, respectively. Generally speaking,stimulation electrode arrays may also be non-invasive, e.g. byadministering and providing transcutaneous stimulation to the spinalcord and/or other parts of the nervous system. Open-loop phasicstimulation may be also provided with external stimulators and invasiveand/or non-invasive electrodes, such as in Functional ElectricalStimulation (FES) of individual muscles, Peripheral Nerve System (PNS)Stimulation of peripheral nerves and/or in transcutaneous spinal cordstimulation. It is also in general possible, that the afore-mentionedstimulation approaches may be combined.

The stimulation parameters for use this open-loop stimulation are chosenfrom the following ranges:

Frequency: 10-1000 Hz with preferred frequencies between 60 and 120 Hz.

Pulse Width: 100-1000 μs for implanted electrodes (invasive) and200-2000 μs for surface electrodes (non-invasive and transcutaneousstimulation).

Amplitudes: 0.1-25 mA or 0.1-15 V for implanted for implanted electrodes(invasive) and 1-250 mA or 1-150 V for surface electrodes (non-invasiveand transcutaneous stimulation).

Pulse shape: any type of charge-balanced pulse, either monophasic orbi-phasic.

Duration of each stage (i.e. stage being used in the context that anopen-loop phasic stimulation program is a pre-defined sequence of stagesthat can activate several sets of active electrodes that in turn affectseveral muscle groups): 50-5000 ms.

Number of stages: approx. 1-10 or selected in the range of betweenapprox. 1-100.

FIG. 2 shows an example workflow of the system 10 for setting up anopen-loop stimulation.

In step S1 a prototype sequence of stimulation based on desiredfunctionalities is determined.

Here, each stage (i.e. stage being used in the context that an open-loopphasic stimulation program is a pre-defined sequence of stages that mayactivate several sets of active electrodes that in turn may affectseveral muscle groups) of the sequence is characterized by a specificduration and waveform (amplitude, pulse width, frequency of activeelectrodes). For protocols that involve stimulation at a specific phaseof movement (as during locomotion), availability of closed-loopstimulation may facilitate determining the prototype of the sequence.

In step S2 the subject (patient) is instructed about his behavior withrespect to the stimulation.

Here, it may be either passive (like in the case of blood pumping) oractive (as in the case of locomotion). In the latter case, the subjectmay synchronize his voluntary behavior with the stages of thestimulation.

Generally speaking, the subject may synchronize his voluntarycontributions to all stages of the stimulation, but typically theyinitiate a movement by concentrating on a single stage, e.g., left hipflexion. Then, to continue the rhythmic movement, the subject maysynchronize to all stages in the sequence they appear.

In step S3 the effects of this stimulation sequence are observed.

Here, the observed effects of this stimulation sequence on the subject,i.e. inter alia subjective reports (interaction between patient andtraining personnel and physician) and relevant physiological parameterssuch as kinematic variables, electromyographic (EMG) activity, bloodpressure, electroencephalography (EEG) and the like are reviewed.

In step S4 one of the stimulation parameters is varied to see the effecton the desired functionalities.

Parameters to be varied are duration of each stage of the sequence,active electrodes for each waveform, amplitudes, pulse widths andfrequencies. This procedure may be repeated and iterated until anoptimum is found.

In step S5 the optimal stimulation parameters are selected and used forthe execution of the task or training.

For example, the sequences for walking comprise at least a firstsequence related to left flexion and right extension, a second sequencerelated to right extension only, third sequence related to leftextension and right flexion and a fourth sequence related to leftextension only.

FIG. 3 shows a schematic diagram of one leg and foot trajectory duringlocomotion enabled by phasic stimulation as specified above inconnection with the sequences for walking, with two patterns ofstimulation applied sequentially, one during the swing phase SP1 and oneduring the stance phase SP2 of the gait.

FIGS. 4A-D show the corresponding activation of the electrodes 18 a onan electrode paddle 19.

In this example, the first sequence SQ1 (FIG. 4A) related to leftflexion and right extension is 400 ms, the second sequence SQ2 (FIG. 4B)related to right extension is 600 ms, the third sequence SQ3 (FIG. 4C)related to left extension and right flexion is 400 ms and the fourthsequence SQ4 (FIG. 4D) related to left extension only is 600 ms.

The electrode configurations corresponding to the sequences SQ1 to SQ4indicated above are further discussed below.

In FIG. 4A activated electrodes 18 a* relate to the stimulation of theleft leg for left flexion.

In FIG. 4A and FIG. 4B activated electrodes 18 a** relate to thestimulation of the right leg for right extension.

In FIG. 4C activated electrode(s) 18 a*** relate to the stimulation ofthe right leg for right flexion.

In FIG. 4C and FIG. 4D activated electrode(s) 18 a**** relate to thestimulation of the left leg for left extension.

The resulting stimulation patterns, which are the result of the specificelectrodes 18 a on the electrode paddle 19 shown in FIGS. 4A-D, are forpromoting respectively flexion and extension of either the left or theright leg.

In this specific example, the right extension and right flexionelectrodes are ‘mono-polar’ selections and the active site of the IPG isset as the return electrode.

FIG. 5 shows the concept and overview of open-loop phasic stimulationfor walking.

As shown in FIG. 5, there is an Onset of Stimulation OS. This Onset ofStimulation OS is done by means of the initialization module 22 and theinitialization data ID.

Here, the initialization module 22 controls the electrical stimulationdevice 16 via the controller 12 based on the initialization data ID suchthat the electrical stimulation device 16 provides neuromodulationsignals and/or neurostimulation signals, for an initialization action ormovement of the subject to do the Onset of Stimulation OS (cf. also FIG.1).

With the volitional initiation of the first step VI the sequences SQ1 toSQ4 are provided as described above.

FIG. 6A and FIG. 6B show the difference between absence and presence ofopen-loop phasic stimulation in connection with the training of apatient P by using the system as shown in FIG. 1. Exemplary patient Phas a chronic incomplete SCI, with his left leg completely paralyzed andwith some residual function in his right leg.

In both cases shown in FIG. 6A and FIG. 6B, the patient is placed in arobotic system supporting 35% of his body weight.

In these conditions and in the absence of open-loop EES (FIG. 6A, left),the patient is unable to initiate a single step and instead attempts tomove his legs using his trunk and arm movements. Leg muscles show almostno EMG activity during this attempted movement.

By contrast, the application of open-loop EES (FIG. 6B, right) enablesthe patient to perform more than 10 consecutive steps with minimalassistance at the hips, showing the natural alternation of left andright stance and swing phases, accompanied by strong rhythmical EMGactivity in all recorded leg muscles.

This shows that open-loop phasic stimulation by using EES enableslocomotion and generates EMG activity in a person with incomplete spinalcord injury.

The above can be summarized in other words as follows:

Locomotion is accomplished via the cyclical coordinated alternation offlexion and extension muscle synergies at specific phases of the gaitcycle. Open-loop phasic stimulation defines a sequence of pre-programmedstimulation patterns that promote movements at each phase of the gaitcycle. Typically, the flexion phase on one leg coincides with theextension phase on the contralateral leg. An example of open-loop phasicstimulation program for locomotion is shown in FIG. 3 and FIG. 4A-D.

In order to use the stimulation for walking, the patient has tosynchronize his attempts to move his leg with the timing of thestimulation (FIG. 5). It is important to understand that the stimulationdoes not move the legs without voluntary inputs from the brain of thepatient. First, the patient feels the onset of the stimulationdischarges in standing position, and then tries to initiate his gaitwith the appropriate timing. It has been observed that that patients mayeasily adjust to this type of stimulation and use it effectively forwalking.

Open-loop phasic stimulation as provided by the system 10 may be alsoused for any cyclical activity on physical training devices (bike,elliptical device, rowing machine):

Using the same principle, open-loop phasic stimulation programs may beimplemented to promote cyclical coordinated leg muscle activity for anytype of cyclical training activity, such as biking, walking on anelliptical device or using a rowing machine. Depending on the context,not all available stimulation patterns need to be used. For example,biking in reclined position requires mostly extension stimulationsrather than flexion. In that case, extension stimulations alternatebetween the left and right leg at a fixed rhythm, for example.

Further stimulation patterns are shown in FIGS. 7A-B to FIGS. 11A-B.

Activated electrodes 18 a of the electrode paddle 19 have the referencenumber 18 a*.

FIG. 7A shows a schematic view of the electrode paddle 19 of the system10 with specifically activated electrodes for left leg stimulation. Suchkind of stimulation may be used to train specifically one leg, here theleft leg.

As can be derived from FIG. 7B, specific left leg stimulation is donefor with a current of 2.0 mA for 1500 ms.

FIG. 8A shows a schematic view of the electrode paddle 19 of the system10 with specifically activated electrodes for stimulation for walkingwith an ambulatory walker.

FIG. 8B shows in greater detail the respective sequences, the specificcurrent and also the time span for right flexion stimulation, rightextension stimulation, left flexion stimulation and left extensionstimulation.

Stage C1 indicates in FIG. 8A and FIG. 8B the stimulation for left ankleextension, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrodes and FIG. 8B shows the stimulation overtime (2.3 mA for 2000 ms between 2000 ms to 4000 ms in the time spanbetween 0 ms to 4000 ms).

Stage C2 indicates in FIG. 8A and FIG. 8B the stimulation for left kneeextension, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (2.7 mA for 2000 ms between 2000 ms to 4000 ms in the timespan between 0 ms to 4000 ms).

Stage C3 indicates in FIG. 8A and FIG. 8B the stimulation for left hipflexion, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (4.8 mA for 500 ms between 0 ms to 500 ms in the time spanbetween 0 ms to 4000 ms).

Stage C4 indicates in FIG. 8A and FIG. 8B the stimulation for left ankleflexion, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (1.5 mA for 500 ms between 0 ms to 500 ms in the time spanbetween 0 ms to 4000 ms).

Stage C5 indicates in FIGS. 8A and 8B the stimulation for right ankleextension, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (0.5 mA for 2000 ms between 0 ms to 2000 ms in the time spanbetween 0 ms to 4000 ms).

Stage C6 indicates in FIGS. 8A and 8B the stimulation for right hipflexion, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (4.6 mA for 500 ms between 2000 ms to 2500 ms in the time spanbetween 0 ms to 4000 ms).

Stage C7 indicates in FIGS. 8A and 8B the stimulation for right ankleflexion, where FIG. 8A shows the activated (dark colored) andnon-activated (white) electrode(s) and FIG. 8B shows the stimulationover time (1.2 mA for 500 ms between 2000 ms to 2500 ms in the time spanbetween 0 ms to 4000 ms).

FIG. 9A shows a schematic view of an electrode paddle 19 of the system10 with specifically activated electrodes (dark colored) for stimulationfor walking at an enhanced rehabilitation stage (challenging scenario).

FIG. 9B shows in greater detail the respective sequences, the specificcurrent and also the time span for right flexion stimulation, rightextension stimulation, left flexion stimulation and left extensionstimulation. For FIGS. 9A-9B, the various stages (C1-C7) are asdescribed above with regard to FIGS. 8A-8B.

FIG. 10A shows a schematic view of an electrode paddle 19 of the system10 with specifically activated electrodes (dark colored) for sacralstimulation to improve sexual function and bladder function.

As can be derived from FIG. 10B, specific caudal stimulation for sacralstimulation to improve sexual function and bladder function is done forwith a current of 4.0 mA for 1500 ms.

FIG. 11A shows a schematic view of the electrode paddle 19 of the system10 with specifically activated electrodes (dark colored) for kneeextension stimulation to facilitate sit-to-stand scenarios.

As can be derived from FIG. 11B, specific stimulation for right kneeextension and specific stimulation for left knee extension is done atthe same time with a current of 3.5 mA for 1000 ms.

As shown in FIG. 12A and FIG. 12B, the system 10 provides a skeletalmuscle pump in order to control the blood pressure of the patient.

Here, stimulation data SD comprise a sequence of stimulation patternsexploiting the skeletal muscle pump for blood pumping from the lowerextremities of the subject in the direction back to the heart of thesubject.

More specifically, the sequences comprise at least a first sequencerelated to stimulation of a muscle M in at least one extremity to relaxthe muscle M (cf. FIG. 12) and at least a second sequence related tostimulation of a muscle in this extremity to contract the muscle, whichmeans that there is less or even no stimulation provided by the system10 (FIG. 12B).

By this, it may be possible to assist the subject with blood pressurecontrol and to avoid a blood pressure drop when the subject or patientwants to stand up, e.g. for starting to walk or the like. Also duringwalking such kind of stimulation may help the patient to perform his/hertraining.

In other words, open-loop phasic stimulation may be provided by thesystem to activate the Skeletal-muscle pump for counteractingorthostatic hypotension:

When a person rises from a horizontal to a vertical position, bloodpools in the lower extremities, and blood pressure decreases. As aresponse, cardiac, vascular, neurological, muscular, and neurohumoralresponses must occur quickly to increase and maintain blood pressure.

If any of these responses are abnormal, e.g., due to a neurologicalcondition, blood pressure and organ perfusion may be reduced. Inindividuals with spinal cord injury, blood pressure may significantlydecrease upon changing body position from a supine position to anupright posture, the physical effect called orthostatic hypotension. Asa result, symptoms of central nervous system hypoperfusion may occur,including feelings of weakness, nausea, headache, neck ache, dizziness,blurred vision, fatigue, tremulousness, palpitations, and impairedcognition.

In turn, this may have a negative impact upon the ability of spinal cordinjured individuals to participate in rehabilitation, such as stretchingmuscle-tendon complexes in a standing position using a standing frame,or participating to active standing training. In individuals with intactnervous system function, the skeletal-muscle pump aids the heart in thecirculation of blood. Muscle contraction in the legs and abdomencompresses veins.

Because veins are equipped with one-way valves V (see FIG. 12A and FIG.12B), blood B in the venous system VS is moved back to the heart. Toillustrate the movement of the volume of blood B trapped between the twovalves V (cf. FIG. 12A), only this volume is hatched/shaded (of course,the blood vessel is in the physiological state completely filled withblood B).

This physical effect through open-loop stimulation may be used tocounteract orthostatic hypotension in individuals with spinal cordinjury.

Stimulation may be set up to generate alternating muscle contractionsand relaxations in the main antigravity and extensor muscles, forexample the calf muscles.

Contraction and relaxation times may be chosen to be similar to thoseduring slow walking.

Left-right alternating stimulation may be used to decreasesimultaneously occurring extension forces that would periodically liftup and down the patient.

Blood pressure Time point of Body (upper/lower Heart rate Stimulationmeasure (mm:ss) position mmHg) (bpm) condition Sitting Stimulation off 0′ Transition to standing frame  1′ Standing  91/59 99  1′55″ in the103/53 88  2′40″ standing  93/52 90  3′50″ frame  98/53 91  5′00″ 107/5983 Stimulation on  7′00″ 117/67 79  8′00″ 117/70 76  9′00″ 116/74 7711′00″ 117/71 80 12′10″ 116/69 80

Table 1: Effect of Open-Loop Phasic Stimulation on Blood Pressure andHeart Rate

Example Embodiment

Table 1 shows the effect of open-loop phasic stimulation on bloodpressure and heart rate after changing body position in an individualwith a low-cervical, chronic, sensory and motor incomplete spinal cordinjury according to an example setup and example embodiment. Otherembodiments are generally possible.

Alternating stimulation was applied through the left and rightelectrodes at the caudal end of an epidurally placed array, which wereactive for 1500 ms each in a free run mode (open-loop mode).

The electrode paddle with electrodes (cf. FIG. 4A-D, showing acorresponding electrode paddle 19 with electrodes 18 a) was placed overthe lumbar and upper sacral spinal cord segments, corresponding here tothe T12 to L1 vertebral levels.

Stimulation frequency was 100 Hz, and amplitude was set at a level thatgenerated alternating contractions in the left and right lower limb,predominantly in the calf and hamstrings muscle groups.

Furthermore, the stimulation data SD comprise a sequence of stimulationpatterns for bringing back the sweating function is specific body partof the patient by increasing the excitability of the underlying neuralcircuits of said body part of the patient at the level of the spinalcord, translesionally, or at supraspinal levels.

Individuals with spinal cord injury are normally not fully able toadjust their body temperature below the level of the injury. One reasonis that their sweating function is compromised below the injury level,likely because the brain (the hypothalamus) does not receive thenecessary message that body temperature needs to be corrected. Symptomsof being too warm include nausea, headache, tiredness, reducedconcentration, low blood pressure, and autonomic dysreflexia. In anindividual with a chronic incomplete, low-cervical SCI the return ofsweating function first in the feet could be observed, followed in theanterior and posterior trunk, and finally in the legs in the course ofintensive locomotor training with phasic open-loop epidural spinal cordstimulation. Thus, phasic open-loop stimulation functions as anessential component in the return of sweating function after spinal cordinjury, either by increasing the excitability of the underlying neuralcircuits at the level of the spinal cord (translesionally, or atsupraspinal levels), and by the intense physical training over aprolonged period of time made possible by the open-loop stimulation.

As already mentioned above, the system 10 as shown in connection withFIG. 1 to FIG. 12B may be an open-loop system.

With such an open-loop system open-loop phasic stimulation may beprovided. In contrast to closed-loop systems, open-loop may beunderstood such that neuromodulation and/or neurostimulation isprovided, but the feedback from the patient is not used or does notinfluence the stimulation data. Also, the stimulation provided by thestimulation device, inter alia the sequences provided, is/aremaintained. This may allow a simplified and reliable system. Also, thesystem may be less complex. It may form an additional system and/orsupplement for existing systems or other systems.

For example, it may be possible that the system comprises and/or isconnected and/or connectable with a closed-loop system forneuromodulation and/or neurostimulation.

So, a combined closed-loop and open-loop system having an open-loopsystem 10 and a closed-loop system 30 can be provided as shown in FIG.13.

The system 10 as shown in greater detail in FIG. 1 (components exceptthe electrodes 18 not shown) with all components is implanted into thepatient P.

The electrode paddle 19 with electrodes 18 a is implanted into thespinal channel of the patient P in the lumbar region of the spinal cord.

There is also a controller 32 for the closed-loop system 30.

This controller 32 is connected to the system 10 via interface 12 b.

The closed-loop system 30 has several sensors 34, 34 a, 34 b, 34 c, 34d, wherein sensors 34, 34 a, 34 b, 34 c are implanted sensors and sensor34 d is a wearable sensor (attached to hand by a glove).

Moreover, the closed-loop system 30 has a Central Nerve System (CNS)stimulation module 36, which may provide CNS stimulation via interface12 b to the electrode paddle 19 and the electrodes 18 a.

There is also a Peripheral Nerve System (PNS) stimulation module 38,which is capable to provide PNS stimulation via at least one electrode40 at a peripheral stimulation site.

The controller 32 receives signals from the various sensors 34, 34 a, 34b, 34 c, 34 d and employs the various electrodes 18 a, 40 of FIG. 13 toadjust stimulation parameters based on the received signals andinstructions stored on a memory of the controller 32.

This allows the use of the open-loop approach for specific, predefinedtasks, whereas the closed-loop approach may be used for other tasks,where the closed-loop approach promises more effect. A broader range ofstimulation capabilities may be provided by such a combination.

In particular, the system 10 is for example here configured such thatthe stimulation data SD may be re-configured or adjusted on the basis ofdata being delivered by the closed-loop system. The re-configurationand/or adjustment may be done in real-time.

Closed-loop applications that depend on real-time kinematic parametersfor enabling or inducing functional movement, e.g. locomotion, includethe detection of some characteristic events of locomotion, e.g. afoot-off event to identify stance-to-swing transition or a certainposition of the ankle with respect to the hip. Gait initiation isparticularly difficult for individuals with severe SCI and compromisesthe quality of the gait event detection for the closed-loop system tofurther enable effective locomotion. We propose that open-loopstimulation will be critical to initiate the first steps in suchpatients, until the closed-loop system can extract critical informationof the stepping and fully take over.

Therefore, the system 10 comprises the initialization module 22 andinitialization data ID, wherein the initialization module 22 isconfigured and arranged to control the electrical stimulation devicebased on the initialization data such that the electrical stimulationdevice provides neuromodulation signals and/or neurostimulation signals,for an initialization action or movement of the subject. Especially, thesystem 10 as shown in FIG. 13 is configured and arranged such that theinitialization module 22 and initialization data ID are used to startthe closed-loop system 30.

Moreover, the open-loop stimulation provided by the system 10 may serveas a ‘rescue mode’ for closed-loop applications of the closed-loopsystem 30.

In case of continuous misdetections of the real-time system of aclosed-loop application of the closed-loop system 30 or in the case of avery inconsistent gait, this will be detected by the controller 32 ofthe closed-loop system 30.

Then, control can be handed over to the controller 12 of the open-loopsystem, e.g. simply by (temporally) switching off the closed-loop system30 or putting the closed-loop system 30 on hold or by re-booting theclosed-loop system 30 or the like.

Thus, open-loop stimulation provided by the system 10 only is used untilthe closed-loop system 30 reliably detects gait events and takes overagain. The switch between open- and closed-loop stimulation systems maybe based on a gait event error detection system (such as inspection ofthe sequence of detected gait events).

Such a gait event error detection system may be a module of theclosed-loop system 30 or may be installed or integrated into thecontroller 32 of the closed-loop system 30.

For these kinds of take over scenarios, the system 10 comprises afallback module 24 and fallback module data FD, the fallback module dataFD being specific stimulation data being stored in the stimulationpattern storage means, wherein the fallback module 24 is configured andarranged to control the electrical stimulation device 16 based on thefallback module data such that the electrical stimulation deviceprovides neuromodulation signals and/or neurostimulation signals, for anactions or movement of the subject, when the closed-loop system isunintentionally out of service.

By this, the operational aspects of a closed-loop system may beincreased and enhanced. In such a case, the system itself has thecapability to provide open-loop stimulation and closed-loop stimulationor the system is combined with a closed-loop system. As open-loopstimulation does not include any feedback from the patient, such anapproach is advantageous to maintain and provide at least basicstimulation capabilities, when closed-loop stimulation is temporarilynot working.

Note that the example control and estimation routines included hereincan be used with various neuromodulation and/or neurostimulation systemconfigurations. The control methods and routines disclosed herein may bestored as executable instructions in non-transitory memory and may becarried out by the control unit in combination with the various sensors,actuators, and other system hardware. The specific routines describedherein may represent one or more of any number of processing strategiessuch as event-driven, interrupt-driven, multi-tasking, multi-threading,and the like. As such, various actions, operations, and/or functionsillustrated may be performed in the sequence illustrated, in parallel,or in some cases omitted. Likewise, the order of processing is notnecessarily required to achieve the features and advantages of theexample embodiments described herein, but is provided for ease ofillustration and description. One or more of the illustrated actions,operations and/or functions may be repeatedly performed depending on theparticular strategy being used. Further, the described actions,operations and/or functions may graphically represent code to beprogrammed into non-transitory memory of the computer readable storagemedium in the control unit, where the described actions are carried outby executing the instructions in a system including the various hardwarecomponents in combination with the electronic control unit.

REFERENCES

-   10 Neuromodulation and/or neuro stimulation system-   12 Controller-   12 a Input means-   12 b Interface-   14 Stimulation pattern storage means-   14 a Temporal stimulation pattern data storage module-   14 b Spatial stimulation pattern data storage module-   14 c Meta data storage module-   16 Electrical stimulation device-   18 Electrical interface-   19 Electrode paddle-   20 Bio-interface-   22 Initialization module-   24 Fallback module-   30 Closed-loop system-   32 Controller-   34 Sensor-   34 a Sensor-   34 b Sensor-   34 c Sensor-   34 d Sensor-   36 Central Nerve System (CNS) stimulation module-   38 Peripheral Nerve System (PNS) stimulation module-   40 Electrode-   18* Activated Electrodes left flexion-   18** Activated Electrodes right extension-   18*** Activated Electrodes right flexion-   18**** Activated Electrodes left extension-   C1 Stage 1-   C2 Stage 2-   C3 Stage 3-   C4 Stage 4-   C5 Stage 5-   C6 Stage 6-   C7 Stage 7-   S1 Step 1 of workflow for setting up an open-loop stimulation-   S2 Step 2 of workflow for setting up an open-loop stimulation-   S3 Step 3 of workflow for setting up an open-loop stimulation-   S4 Step 4 of workflow for setting up an open-loop stimulation-   S5 Step 5 of workflow for setting up an open-loop stimulation-   SP1 Swing phase-   SP2 Stance phase-   SQ1 First sequence-   SQ2 Second sequence-   SQ3 Third sequence-   SQ4 Fourth sequence-   FD Fallback module data-   ID Initialization data-   SC Spatial component-   SD Stimulation data-   TC Temporal component-   OS Onset of Stimulation-   VI Volitional initiation of the first step-   B Blood-   VS Venous System-   V One-way valve-   P Patient

The invention claimed is:
 1. A system for neuromodulation and/orneurostimulation, for the treatment of a subject, comprising at least astimulation controller, at least a stimulation pattern storage drivewhich is connected to the stimulation controller and which comprisesstimulation data, at least an electrical stimulation device, at least anelectrical interface between the electrical stimulation device and thesubject, the electrical interface being connectable with at least abio-interface of or with a nervous system of the subject, wherein theelectrical interface and the bio-interface are arranged such thatsignals and/or data are exchanged from the electrical interface to thebio-interface or vice versa, wherein the stimulation data arepre-programmed patterns which comprise at least a spatial componentwhich is related to a part of the nervous system being stimulated and atemporal component which is related to a time at which the spatialcomponent is applied; and wherein the stimulation controller is capableto send configuration signals on a basis of the stimulation data to theelectrical stimulation device such that via the electrical interface anelectrical stimulation is provided to the bio-interface, wherein theelectrical stimulation provided is characterized by one or morestimulation parameters that vary over time in a pre-programmed manner,and where the electrical stimulation provided is open-loop phasicstimulation, wherein the open-loop phasic stimulation is phasicstimulation of the nervous system of the subject free from feedbacksystems.
 2. The system according to claim 1, wherein the stimulationpattern storage drive comprises a spatial stimulation pattern datastorage module for the spatial component and that the stimulationpattern storage drive comprises a temporal stimulation pattern datastorage module for the temporal component, and wherein the stimulationcontroller is capable to access the modules and/or to read out themodules independently from each other.
 3. The system according to claim1, wherein the stimulation data comprise data related to the one or morestimulation parameters, where the one or more stimulation parametersinclude stimulation frequency, stimulation amplitude, stimulationcurrent, and/or pulse width.
 4. The system according to claim 1, whereinthe electrical stimulation device comprises a plurality of electrodesand wherein the spatial component comprises data related to activationand non-activation of defined subsets of the plurality of electrodes. 5.The system according to claim 1, wherein the stimulation data comprisemeta data, which link the spatial component and the temporal componentto each other.
 6. The system according to claim 1, wherein thestimulation data comprise a sequence of stimulation patterns for acyclic activity including a gait cycle, cycling, swimming, arehabilitation activity, and/or a training activity.
 7. The systemaccording to claim 6, wherein the sequences comprise a plurality ofordered stages which are arranged to form in their order a replicationof physiological activation signals of relevant muscle groups at anappropriate time for a specific task or movement of the subject, thespecific task or movement being at least one of walking, standing,standing up, sitting down, climbing staircases, cycling, lifting a footof the subject, placing and/or moving an extremity, trunk and/or thehead of the subject, and wherein when the specific task is walking thesequences comprise at least a first sequence related to left flexion andright extension, a second sequence related to right extension only, athird sequence related to left extension and right flexion, and a fourthsequence related to left extension only.
 8. The system according toclaim 1, wherein the stimulation data comprise a sequence of stimulationpatterns exploiting a skeletal muscle pump for blood pumping fromextremities of the subject in a direction back to a heart of thesubject, wherein the sequence comprises at least a first sequencerelated to stimulation of a muscle in at least one extremity of thesubject to contract the muscle and at least a second sequence related tostimulation of the muscle in the at least one extremity to relax themuscle.
 9. The system according to claim 1, wherein the system is anopen-loop system.
 10. The system according to claim 9, wherein theopen-loop system is connected and/or connectable with a closed-loopsystem for neuromodulation and/or neurostimulation.
 11. The systemaccording to claim 10, wherein the open-loop system is configured suchthat the stimulation data is capable to be re-configured and/or adjustedon the basis of data being delivered by the closed-loop system, whereinthe re-configuration and/or adjustment is done in real-time.
 12. Thesystem according to claim 10, wherein the stimulation data comprise asequence of stimulation patterns comprising at least one startingsequence.
 13. The system according to claim 10, wherein the open-loopsystem comprises an initialization module and initialization data, theinitialization data being specific stimulation data being stored in thestimulation pattern storage drive, wherein the initialization module isconfigured and arranged to control the electrical stimulation devicebased on the initialization data such that the electrical stimulationdevice provides neuromodulation signals and/or neurostimulation signals,for an initialization action or movement of the subject.
 14. The systemaccording to claim 13, wherein the open-loop system is configured andarranged such that the initialization module and initialization data areused to start the closed-loop system.
 15. The system according to claim10, wherein the open-loop system comprises a fallback module andfallback module data, the fallback module data being specificstimulation data being stored in the stimulation pattern storage drive,wherein the fallback module is configured and arranged to control theelectrical stimulation device based on the fallback module data suchthat the electrical stimulation device provides neuromodulation signals,wherein the fallback module data are neurostimulation signals for anaction or movement of the subject, when the closed-loop system for saidsubject being connected with the open-loop system is unintentionally outof service.
 16. A method for neuromodulation and/or neurostimulation forthe treatment of a subject, comprising: using at least an electricalstimulation device and at least an electrical interface between theelectrical stimulation device and the subject, and at least a subjectneural interface being connected to the electrical interface, whereinthe subject is stimulated with the electrical stimulation device viausing stimulation pattern data, where the stimulation pattern datainclude pre-programmed patterns comprising at least: a spatial componentrelated to a part of a nervous system of the subject being stimulated; atemporal component related to a time at which each spatial component isapplied; and wherein, based on the stimulation pattern data theelectrical stimulation device provides via the electrical interface, anelectrical stimulation to the subject neural interface, where theelectrical stimulation provided is characterized by stimulationparameters that vary over time in a pre-programmed manner, and where theelectrical stimulation provided is open-loop phasic stimulation, whereinthe open-loop phasic stimulation is phasic stimulation of the nervoussystem of the subject free from feedback systems.
 17. The method ofclaim 16, wherein the electrical stimulation is provided in one or moreof sequences, cyclically, and/or repeatedly.
 18. The method of claim 17,wherein the sequences comprise a plurality of ordered sequences whichare arranged in that they form in their order a replication ofphysiological activation signals of particular muscle groups at anappropriate time for a specific task or movement of the subject, thespecific task or movement being at least one of walking, standing up,sitting down, climbing staircases, cycling, lifting a foot, and placingand/or moving an extremity or a head of the subject.
 19. The method ofclaim 16, wherein the electrical stimulation stimulates a muscle ormuscles of the subject for blood pumping from one or more extremities ofthe subject in a direction back to a heart of the subject.
 20. Themethod of claim 19, wherein under conditions where the electricalstimulation stimulates a muscle or muscles of the subject, at least onemuscle is stimulated to contract and relax alternately.